Petroleum asphalt-coated silica as the stationary phase for liquid chromatography

Owing to high specific surface area and excellent chemical stability, carbon materials as stationary phases demonstrated significant advantages. However, their practical application was limited by high cost and complex synthesis process. In this work, the low-cost petroleum asphalt (PA) was successfully transformed into a stationary phase for high-performance liquid chromatography. Through a facile coating way, the PA was immobilized onto porous silica for producing a new stationary phase. As the concentration of asphalt in the coating solution was increased, the carbon content of the stationary phases rose from 6.67 % (SiO₂@PA-1) to 18.80 % (SiO₂@PA-3), leading to the enhanced selectivity toward polycyclic aromatic hydrocarbons (PAHs). The separation selectivity (α=1.16-1.62) of PAHs by SiO₂@PA-3 column was superior to that by C₁₈ column (α=1.00-1.49), attributed to the π-stacking and hydrophobic methanism from PA phase. The SiO₂@PA-3 column separately achieved baseline separation of some alkylbenzenes and tetrabromobisphenol A derivatives. Notably, it also effectively separated several isomers of PAHs, phenols, and anilines, with a column efficiency reaching 38,260 plates m^-1. Then, a HPLC-DAD method with a linear range (0.33-12.5 mg L^-1) and detection limits (0.10-0.20 mg L^-1), was developed for determining tetrabromobisphenol A derivatives in water samples. This research proposed a cost-effective and facile strategy for the development of stationary phase.